EasyExcel-Export-Demo

CellRangeAddress cellRangeAddress = new CellRangeAddress(起始行，结尾行，起始列，结尾列)；
sheet.addMergedRegionUnsafe(cellRangeAddress);

ExcelWriter screenTemplateExcelWriter = EasyExcel
        .write(templateOut)   								// 导出最终临时文件
        .withTemplate(templateFileName)						// 使用的模板
        .registerWriteHandler(new XXXStrategy(需要的参数))	// 自定义单元格合并策略
        .build();

@Service
public class ScreenServiceImpl implements ScreenService {
    @Override
    public void export(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) {
        // HttpServletResponse消息头参数设置
        String filename = "exportFile.xlsx";
        httpServletResponse.addHeader(HttpHeaders.CONTENT_DISPOSITION, "attachment;filename=" + filename);
        httpServletResponse.setContentType("application/octet-stream;charset=UTF-8");
        httpServletResponse.addHeader("Pragma", "no-cache");
        httpServletResponse.addHeader("Cache-Control", "no-cache");
   
        // 通过ClassPathResource获取/resources/template下的模板文件
        ClassPathResource classPathResource = new ClassPathResource("template/screenTemplate.xlsx");
        
        // 这里用try-with-resource
        try (
                // 获取模板文件
                InputStream screenParamTemplateFileName = classPathResource.getInputStream();

                OutputStream screenOut = httpServletResponse.getOutputStream();
                BufferedOutputStream screenBos = new BufferedOutputStream(screenOut);
        ) {
            // --------------------------------基本配置--------------------------------
            // 设置内容的策略
            WriteCellStyle contentWriteCellStyle = new WriteCellStyle();
            // 设置内容水平居中对齐
            contentWriteCellStyle.setHorizontalAlignment(HorizontalAlignment.CENTER);
            // 设置内容垂直居中对齐
            contentWriteCellStyle.setVerticalAlignment(VerticalAlignment.CENTER);
            // 自动换行
            contentWriteCellStyle.setWrapped(true);
            // 设置字体样式和大小
            WriteFont contentWriteFont = new WriteFont();
            contentWriteFont.setFontHeightInPoints((short) 12);
            contentWriteFont.setFontName("微软雅黑");
            contentWriteCellStyle.setWriteFont(contentWriteFont);
            // 配置横向填充
            FillConfig fillConfig = FillConfig.builder().direction(WriteDirectionEnum.HORIZONTAL).build();
            // sheet名称
            WriteSheet writeSheet = EasyExcel.writerSheet("sheet0").build();
            // --------------------------------基本配置--------------------------------


            // ---------------------模拟获取第一部分的表格数据、表头参数---------------------
            List<ScreenGatherDTO> screenGatherDTOList = new ArrayList<>();
            // 构造5个产品数据
            for (int i = 1; i <= 5; i++) {
                // 每份数据乘以4，为了合并单元格做准备
                for (int j = 0; j < 4; j++) {
                    ScreenGatherDTO screenGatherDTO = new ScreenGatherDTO();
                    screenGatherDTO.setScreenSize(String.valueOf(i * 10));
                    screenGatherDTO.setSupplier("厂商" + i);
                    screenGatherDTO.setPartMode("型号" + i);
                    screenGatherDTO.setResolution("1080P");
                    screenGatherDTO.setRefreshRate("60Hz");
                    screenGatherDTO.setPanel("IPS");
                    screenGatherDTOList.add(screenGatherDTO);
                }
            }
            if (CollectionUtils.isNotEmpty(screenGatherDTOList)) {
                for (int i = 0; i < screenGatherDTOList.size(); i++) {
                    // 在屏规格末尾加上表格模板参数
                    screenGatherDTOList.get(i).setValueTemplateParam("{screenValueTemplateParam" + i + ".value}");
                }
            }

            // 填充第一个表头的单元格
            ScreenValueExcelDTO screenValueExcelDTO = new ScreenValueExcelDTO();
            List<ScreenValueExcelDTO> screenValueExcelDTOList = new ArrayList<>();
            screenValueExcelDTO.setValue("产品测试");
            screenValueExcelDTOList.add(screenValueExcelDTO);

            // 在屏规格末尾加上表头模板参数
            List<ScreenValueExcelDTO> screenTableExcelDTOList = new ArrayList<>();
            for (int i = 0; i < 4; i++) {
                ScreenValueExcelDTO screenTableExcelDTO = new ScreenValueExcelDTO();
                switch (i) {
                    case 0:
                        screenTableExcelDTO.setValue("{screenTableExcelDTOList.modelName}");
                        break;
                    case 1:
                        screenTableExcelDTO.setValue("{screenTableExcelDTOList.testItemCategory}");
                        break;
                    case 2:
                        screenTableExcelDTO.setValue("{screenTableExcelDTOList.testItemName}");
                        break;
                    case 3:
                        screenTableExcelDTO.setValue("{screenTableExcelDTOList.subTestItemName}");
                        break;
                    default:
                        break;
                }
                screenTableExcelDTOList.add(screenTableExcelDTO);
            }
            // ---------------------模拟获取第一部分的表格数据、表头参数---------------------


            // --------------------------------第一次导出--------------------------------
            ExcelWriter screenTemplateExcelWriter = EasyExcel
                    .write(screenBos)   // 导出临时文件，使用的是BufferedOutputStream
                    .withTemplate(screenParamTemplateFileName)  // 使用的模板
                    .registerWriteHandler(new ScreenValueMergeStrategy(screenGatherDTOList, 1, 6, 5))   // 自定义单元格合并策略
                    .registerWriteHandler(new HorizontalCellStyleStrategy(null, contentWriteCellStyle)) // 只配置内容策略，头部为null
                    .build();
            // 填充屏规格表格数据
            screenTemplateExcelWriter.fill(new FillWrapper("screenGatherDTOList", screenGatherDTOList), writeSheet);
            // 填充第一个表头的单元格
            screenTemplateExcelWriter.fill(new FillWrapper("screenValueExcelDTOList", screenValueExcelDTOList), writeSheet);
            // 填充表头模板参数
            screenTemplateExcelWriter.fill(new FillWrapper("screenTableExcelDTOList", screenTableExcelDTOList), writeSheet);
            screenTemplateExcelWriter.finish();
            // --------------------------------第一次导出--------------------------------
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}

public class ScreenValueMergeStrategy extends AbstractMergeStrategy {
    /**
     * 分组，每几行合并一次
     */
    private List<Integer> exportFieldGroupCountList;

    /**
     * 合并的目标开始列索引
     */
    private Integer targetBeginColIndex;
    /**
     * 合并的目标结束列索引
     */
    private Integer targetEndColIndex;
    /**
     * 需要开始合并单元格的首行索引
     */
    private Integer firstRowIndex;

    public ScreenValueMergeStrategy() {
    }

    /**
     * @param exportDataList      待合并目标行的值
     * @param targetBeginColIndex 合并的目标开始列索引
     * @param targetEndColIndex   合并的目标结束列索引
     * @param firstRowIndex       需要开始合并单元格的首行索引
     */
    public ScreenValueMergeStrategy(List<ScreenGatherDTO> exportDataList, Integer targetBeginColIndex, Integer targetEndColIndex, Integer firstRowIndex) {
        this.exportFieldGroupCountList = getGroupCountList(exportDataList);
        this.targetBeginColIndex = targetBeginColIndex;
        this.targetEndColIndex = targetEndColIndex;
        this.firstRowIndex = firstRowIndex;
    }

    @Override
    protected void merge(Sheet sheet, Cell cell, Head head, Integer relativeRowIndex) {
        if (cell.getRowIndex() == this.firstRowIndex && cell.getColumnIndex() >= targetBeginColIndex - 1 && cell.getColumnIndex() <= targetEndColIndex - 1) {
            int rowCount = this.firstRowIndex;
            for (Integer count : exportFieldGroupCountList) {
                if (count == 1) {
                    rowCount += count;
                    continue;
                }
                // 合并单元格
                CellRangeAddress cellRangeAddress;
                for (int i = 0; i < targetEndColIndex - targetBeginColIndex + 1; i++) {
                    cellRangeAddress = new CellRangeAddress(rowCount - 1, rowCount + count - 2, i, i);
                    sheet.addMergedRegionUnsafe(cellRangeAddress);
                }
                rowCount += count;
            }
        }
    }

    /**
     * 该方法将目标列根据值是否相同连续可合并，存储可合并的行数
     *
     * @param exportDataList
     * @return
     */
    private List<Integer> getGroupCountList(List<ScreenGatherDTO> exportDataList) {
        if (CollectionUtils.isEmpty(exportDataList)) {
            return new ArrayList<>();
        }
        List<Integer> groupCountList = new ArrayList<>();
        int count = 1;
        for (int i = 1; i < exportDataList.size(); i++) {
            boolean equals = exportDataList.get(i).getPartMode().equals(exportDataList.get(i - 1).getPartMode());

            if (equals) {
                count++;
            } else {
                groupCountList.add(count);
                count = 1;
            }
        }
        // 处理完最后一条后
        groupCountList.add(count);
        return groupCountList;
    }
}